Foreign body removal device and drive device for foreign body removal device

ABSTRACT

Of moving directions of a piston, the direction in which high-pressure air is delivered is a delivery direction, and the direction in the opposite direction from the delivery direction is a force accumulation direction. The piston is moved in the force accumulation direction by the moving mechanism, and moved in the delivery direction by the biasing force of the biasing spring in response to the release of the moving force exerted by the moving mechanism. The cylinder is provided with: a piston supporting portion that supports the piston; and a connection protrusion that has a delivery path for delivering the high-pressure air to the nozzle. The inner surface of an end of the piston supporting portion in the delivery direction is formed as a closed surface. The delivery path is located further toward the force accumulation direction than the closed surface is.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority to JapanesePatent Application No. 2014-258935, filed on Dec. 22, 2014, and JapanesePatent Application No. 2015-032139, filed on Feb. 20, 2015, thedisclosures of which are incorporated herein by reference in theirentirety.

BACKGROUND Technical Field

The present invention relates to a technical field of a foreign matterremoval device configured to wash an object to be washed by injectinghigh-pressure air from a nozzle and a removal drive device configured todrive the foreign matter removal device.

Related Art

Various structures are provided in a structural object such as avehicle. Of the structures, for example, for an in-vehicle camera, avehicle lamp and a rearview mirror, it is desirable to remove foreignmatters such as moisture, mud and dust so as to ensure favorablevisibility. For example, the in-vehicle camera is used as a device fordisplaying a video on a display so as to check the rear of the vehicleor to check a position on an outside of the vehicle, which is hardlyvisible to a driver. However, an imaging unit is often contaminated bymud scattered during traveling of the vehicle or water droplets attachedthereto during rainy weather traveling or the like, so that the videodisplayed on the display is blurred, which may cause interruption of thechecking.

Thus, for example, there has been known a foreign matters removal deviceconfigured to remove foreign matters such as moisture, mud and dustattached to the imaging unit of the in-vehicle camera by injectinghigh-pressure air from a nozzle to the in-vehicle camera (for example,refer to Japanese Patent Application Publication No. 2001-171491A,referred herein as Patent Document 1).

In the foreign matter removal device disclosed in Patent Document 1, thehigh-pressure air is injected from a compressed air generation unittowards the imaging unit to blow-off the mud and water droplets, therebyaddressing the contamination of the imaging unit.

The foreign matter removal device for addressing the contamination ofthe imaging unit by the compressed air has a merit in that a liquidstorage tank is not required and the injected liquid does not remain onthe imaging unit, as compared to a foreign matter removal device foraddressing the contamination by injecting high-pressure liquid such aswater.

Also, there has been known a vehicle in which a camera is mounted so asfor a driver to check the rear of the vehicle and the surroundingsituation. For example, a rear camera is mounted so that the driver cancheck the rear by displaying an image captured by the rear camera on amonitor screen in the vicinity of a driver seat when reversing thevehicle. In this case, it is favorable to remove the foreign matterssuch as dirt, water droplets and the like attached on an imaging surfaceof the camera so as to clearly recognize the captured image. To thisend, a vehicle having a cleaner (a foreign matter removal device)configured to remove the foreign matters by injecting air or water tothe imaging surface has been also suggested.

Japanese Patent Application Publication No. 2006-211443A, referredherein as Patent Document 2, discloses a configuration having a cleanerconfigured to remove the dirt of a camera lens mounted in a vehicle.

SUMMARY OF THE INVENTION

The foreign matter removal device configured to address thecontamination of the imaging unit by the high-pressure air has theabove-described merit. However, the high-pressure air generation unitconfigured to repeatedly generate the high-pressure air and torepeatedly inject the generated high-pressure air is required. Also, anoperating noise, which is to be caused due to contacts betweenrespective parts of the high-pressure air generation unit when therespective parts repeatedly perform an operation, may be generateddepending on structures of the high-pressure air generation unit.

The operating noise may be recognized as abnormal sound to a user, forexample, a driver or a passenger of the vehicle. In this case, thedriver or passenger may feel uncomfortable, and the components may bedamaged or out of order, depending on degrees of the contacts betweenthe respective parts.

Also, a removal drive device configured to drive a motor of the foreignmatter removal device for vehicle is required to execute a process ofremoving the foreign matters at appropriate timing.

In the meantime, it is preferable to avoid complication of routing of apower supply line, a ground line, a control line and the like in thevehicle.

For example, it is considered to control the removal drive device by anECU (electronic control unit) or the like of the vehicle, therebyexecuting the foreign matter removal operation. According to thisscheme, it is possible to highly control the foreign matter removalexecution timing. In this case, however, a wiring (dedicated line) of acontrol line from the ECU is required, in addition to the power supplyline and the ground line, so that it may be difficult to make the wiringdepending on a vehicle type or a camera mounting position and a standbytime period at a power feeding state may be prolonged and a malfunctionmay be thus caused.

In the meantime, when operating the removal drive device only by thepower supply line and the ground line, the wiring is easily made but acircuit system of driving the motor simply depending on the powerfeeding is configured, so that it is not possible to perform complexcontrol.

One or more embodiments of the present invention prevents occurrence ofan abnormal sound by avoiding contacts between respective parts.

One or more embodiments of the present invention simplifies a wiringconfiguration and to enable an appropriate foreign matter removaldriving.

A foreign matter removal device of the present invention includes acylinder in which air is introduced, a piston movably supported to thecylinder and configured to deliver the air introduced into the cylinderas high-pressure air, a nozzle configured to inject the high-pressureair delivered by the piston towards an object to be washed, an urgingspring configured to urge the piston, and a moving mechanism configuredto move the piston to a predetermined position by applying a movingforce to the piston, wherein regarding a moving direction of the piston,a direction in which the high-pressure air is to be delivered is adelivery direction and an opposite direction to the delivery directionis a force accumulation direction, wherein the piston is configured tomove in the force accumulation direction by the moving mechanism and tomove in the delivery direction by an urging force of the urging springin response to release of the moving force applied by the movingmechanism at the predetermined position, wherein the cylinder isprovided with a piston support part configured to movably support thepiston and a coupling protrusion having a delivery path, which continuesto the piston support part and is configured to deliver thehigh-pressure air towards the nozzle, wherein an inner surface of an endportion of the piston support part in the delivery direction is formedas a closed surface, and wherein the delivery path is located furthertowards the force accumulation direction than the closed surface.

With this configuration, when the piston is moved in the deliverydirection, compressed air is interposed between the piston and theclosed surface of the cylinder.

In the foreign matter removal device, preferably, the moving mechanismincludes a main driving gear configured to rotate by a driving force ofa motor and a driven gear configured to engage with the main drivinggear and to rotate in association with rotation of the main drivinggear, and the driving force of the motor is to be transmitted to thepiston via the main driving gear and the driven gear.

With this configuration, a reduction mechanism where a large reductionratio is to be obtained by a simple mechanism having a small number ofcomponents is configured by using the main driving gear and the drivengear.

In the foreign matter removal device, preferably, a rack coupled to thepiston is provided, the driven gear is provided with a pinion that is tobe engaged with the rack, a gear part is provided at a part of an outerperiphery of the pinion, and a part of the outer periphery of the pinionwhere the gear part is not provided is formed as a toothless part.

With this configuration, when the rack is located at the toothless partof the pinion, the piston is moved in the delivery direction by theurging force of the urging spring.

In the foreign matter removal device, a plurality of the gear parts ispreferably formed with being spaced in a circumferential direction.

With this configuration, the number of times of injection of thehigh-pressure air from the nozzle increases during one rotation of thepinion.

In the foreign matter removal device, preferably, a worm is used as themain driving gear and a worm wheel is used as the driven gear.

With this configuration, a reduction mechanism where a large reductionratio is to be obtained by a simple configuration is configured.

A foreign matter removal device of the present invention includes acylinder in which air is introduced, a piston movably supported to thecylinder and configured to deliver the air introduced into the cylinderas high-pressure air, a nozzle configured to inject the high-pressureair delivered by the piston towards an object to be washed, an urgingspring configured to urge the piston, and a moving mechanism configuredto move the piston to a predetermined position by applying a movingforce to the piston, wherein regarding a moving direction of the piston,a direction in which the high-pressure air is to be delivered is adelivery direction and an opposite direction to the delivery directionis a force accumulation direction, wherein the piston is configured tomove in the force accumulation direction by the moving mechanism and tomove in the delivery direction by an urging force of the urging springin response to release of the moving force applied by the movingmechanism at the predetermined position, and wherein when the piston ismoved in the delivery direction, a part of the air in the cylinder iscompressed, so that compressed air is generated and is retained at anend portion in the cylinder in the delivery direction.

With this configuration, when the piston is moved in the deliverydirection, the compressed air is interposed between the piston and theend portion of the cylinder in the delivery direction.

A removal drive device of the present invention is a removal drivedevice mounted on a vehicle and configured to drive a foreign matterremoval device configured to remove attached foreign matters, andincludes a first terminal connected to a power supply line in thevehicle, a second terminal connected to a ground line in the vehicle, amotor driver configured to supply driving current to a motor of theforeign matter removal device and to enable the foreign matter removaldevice to execute a foreign matter removal operation, and an operationsetting unit configured to instruct the motor driver to supply thedriving current for a first predetermined time, as a power supplyvoltage is applied to the first terminal at a state where the secondterminal is connected to a ground.

The power supply line and the ground line are connected with the firstterminal and the second terminal, so that a minimum wiring configurationis obtained. When a voltage between a power supply voltage and a groundis applied between the first and second terminals, which is a trigger,the operation setting unit sets a foreign matter removal drive time(first predetermined time).

In the removal drive device, the first terminal may be connected to thepower supply line to which a power supply voltage is supplied as thevehicle falls within a reverse range.

When the foreign matter removal device sets a rear camera of the vehicleas a target of the foreign matter removal, the foreign matter removal ispreferably executed upon operation start of the rear camera. Therefore,when the first terminal is connected to the power supply line to which apower supply voltage is supplied as the vehicle falls within a reverserange, it is possible to start the foreign matter removal operation atappropriate timing.

In the removal drive device, the operation setting unit is preferablyconfigured to control the motor driver not to supply the driving currentfor a second predetermined time after the power supply voltage isapplied to the first terminal at the state where the second terminal isconnected to the ground.

Thereby, when a shift lever operation of a driver passes the reverserange or when the power supply voltage is supplied to the first terminalfor only a moment by any trigger, a useless foreign matter removaloperation is not performed.

In the removal drive device, the second terminal is selectivelyconnected to a predetermined voltage point and the ground, and theoperation setting unit controls the motor driver to supply the drivingcurrent when the second terminal shifts from a potential of thepredetermined voltage point to a ground potential at a state where thepower supply voltage is applied to the first terminal.

That is, the operation of the removal drive device can be executed bythe control at the ground line-side, too.

The removal drive device may further include a voltage conversion unitconfigured to generate a driving voltage of the motor by boosting ordropping the power supply voltage that is to be supplied to the firstterminal.

The voltage conversion is performed on the assumption that the powersupply line connected to the first terminal is not always a power supplyline of a specific voltage, depending on a vehicle type or a mountingposition. Thereby, it is possible to improve the degree of freedom ofwiring.

According to the foreign matter removal device of the present invention,when the piston is moved in the delivery direction, the compressed airis interposed between the piston and the end portion of the cylinder inthe delivery direction. Therefore, it is possible to prevent occurrenceof an abnormal sound and the like by avoiding contact between the pistonand the end portion of the cylinder in the delivery direction.

Also, according to the removal drive device of the present invention, itis possible to execute the foreign matter removal operation for anappropriate time period by the foreign matter removal device with theminimum wiring configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a foreign matter removal device,depicting an illustrative embodiment of a foreign matter removal deviceof the present invention, together with FIGS. 2 to 13.

FIG. 2 depicts an internal structure of a high-pressure air generationunit.

FIG. 3 is an enlarged perspective view depicting a worm wheel, a pistonand a rack.

FIG. 4 is an enlarged sectional view depicting a state where the pistonis located at a top dead center.

FIG. 5 is an enlarged sectional view depicting a state where the pistonis located at a bottom dead center.

FIG. 6 is an enlarged sectional view depicting a cylinder and thepiston.

FIG. 7 is a sectional view depicting an initial state, which illustratesoperations of the foreign matter removal device, together with FIGS. 8to 10.

FIG. 8 is a sectional view depicting a state where the piston is movingtowards the bottom dead center.

FIG. 9 is a sectional view depicting a state where the piston has beenmoved to the bottom dead center.

FIG. 10 is a sectional view depicting a state where the piston is movingtowards the top dead center.

FIG. 11 depicts an internal structure of the high-pressure airgeneration unit in which a moving mechanism of a first modifiedembodiment is used.

FIG. 12 depicts an internal structure of the high-pressure airgeneration unit in which a moving mechanism of a second modifiedembodiment is used.

FIG. 13 depicts an internal structure of the high-pressure airgeneration unit in which a moving mechanism of a third modifiedembodiment is used.

FIG. 14 is a block diagram of a first illustrative embodiment of aremoval drive device.

FIGS. 15A and 15B illustrate operations of the first illustrativeembodiment of the removal drive device.

FIG. 16 is a circuit diagram of the first illustrative embodiment of theremoval drive device.

FIG. 17 is a circuit diagram of a second illustrative embodiment of theremoval drive device.

FIGS. 18A and 18B illustrate operations of a third illustrativeembodiment of the removal drive device.

FIG. 19 is a circuit diagram of the third illustrative embodiment of theremoval drive device.

DETAILED DESCRIPTION

Hereinafter, illustrative embodiments for implementing a foreignmaterial removal device of the present invention will be described withreference to the accompanying drawings. In embodiments of the invention,numerous specific details are set forth in order to provide a morethorough understanding of the invention. However, it will be apparent toone of ordinary skill in the art that the invention may be practicedwithout these specific details. In other instances, well-known featureshave not been described in detail to avoid obscuring the invention.

Meanwhile, in the below, an example where the foreign material removaldevice of the present invention is applied to a device for removingforeign matters attached to an in-vehicle camera is described. However,the foreign material removal device of the present invention is notlimited to the device for removing foreign matters attached to thein-vehicle camera. For example, the foreign matter removal device of thepresent invention is widely applicable as a device for removing foreignmatters attached to various structures, in particular, as a foreignmatter removal device for removing foreign matters attached to astructure provided in a vehicle, such as a vehicle lamp, a window, amirror and a collision prevention sensor.

The foreign matter removal device to be described later includes acylinder, a piston and a nozzle, and is configured to injecthigh-pressure air from the nozzle as the piston is moved relative to thecylinder.

In below descriptions, a front and rear direction, an upper and lowerdirection and a right and left direction are described by using a movingdirection of the piston as a front and rear direction. Meanwhile, thefront and rear direction, the upper and lower direction and the rightand left direction to be described later are provided only forconvenience of explanations. The illustrative embodiments of presentinvention are not limited to these directions.

<Configuration of Foreign Matter Removal Device>

A foreign matter removal device 1 has a function of washing anin-vehicle camera 100 for checking the rear of a vehicle, for example,and is mounted to a rear end-side of a vehicle body (not shown).

The foreign matter removal device 1 includes a nozzle unit 2, a piping 3and a high-pressure air generation unit 4 (refer to FIG. 1).

The nozzle unit 2 has a mounting bracket 5 and a nozzle 6. The mountingbracket 5 is mounted to a rear end portion of the vehicle body. Thenozzle 6 has a cylindrical flow part 6 a extending in the front and reardirection and an injection part 6 b continuous to a rear end of the flowpart 6 a, and is formed integrally with the mounting bracket 5.

The nozzle unit 2 is formed integrally with the in-vehicle camera 100.The in-vehicle camera 100 has an imaging unit. A rear end portion of theimaging unit is configured as a lens part 101. Accordingly, thein-vehicle camera 100 is configured to capture an image of a subjectthrough the lens part 101.

As described above, in the foreign matter removal device 1, the nozzle 6is formed integrally with the in-vehicle camera 100. Therefore, thenozzle 6 and the in-vehicle camera 100 can be simultaneously mounted tothe vehicle body by a single operation, so that the mounting operationthereof to the vehicle body can be easily and quickly performed, whichimproves the operability.

The piping 3 is a hose made of resin or rubber, for example. A front endportion thereof is coupled to one end portion of a cylinder (to bedescribed later) of the high-pressure air generation unit 4 and a rearend portion thereof is coupled to a front end portion of the flow part 6a of the nozzle 6.

The high-pressure air generation unit 4 includes a case body 7 and amoving mechanism 8 disposed in the case body 7 (refer to FIG. 2). Thehigh-pressure air generation unit 4 is mounted to a part of the vehiclebody in the vehicle.

An interior of the case body 7 is formed as an arrangement space 9,which has a motor arranging part 9 a, a worm arranging part 9 b and agear arranging part 9 c. The motor arranging part 9 a and the wormarranging part 9 b are positioned in communication with each other inthe front and rear direction, and the worm arranging part 9 b and thegear arranging part 9 c are positioned in communication with each otherin the upper and lower direction. An insertion hole 9 d penetrating inthe front and rear direction is formed at a rear end portion of the casebody 7. The insertion hole 9 d is in communication with the outside ofthe case body 7 and the gear arranging part 9 c.

The case body 7 is provided with a support shaft part 7 a protrudinglaterally. The support shaft part 7 a is positioned in the geararranging part 9 c.

The moving mechanism 8 includes a motor 10, a worm 11 and a worm wheel12.

The motor 10 has a main body part 10 a and a motor shaft 10 b. The mainbody part 10 a is arranged in the motor arranging part 9 a (refer toFIG. 2).

The worm 11 is fixedly coupled to the motor shaft 10 b and is arrangedin the worm arranging part 9 b. The worm 11 functions as the maindriving gear.

The worm wheel 12 functions as the driven gear and is configured byintegrally forming a helical gear 13 and a pinion 14 protrudinglaterally from a central portion of the helical gear 13 (refer to FIGS.2 and 3). The worm wheel 12 is arranged in the gear arranging part 9 c,and is supported at a central portion thereof to the support shaft part7 a of the case body 7 via the bearing 15.

The helical gear 13 is engaged with the worm 11.

The pinion 14 is provided concentrically with the helical gear 13 andhas an annular part 16 externally fitted and supported to the bearing 15and gear parts 17, 17, 17 provided on an outer periphery of the annularpart 16. The gear parts 17, 17, 17 are provided with being equallyspaced in a circumferential direction.

The pinion 14 has a diameter of a tooth tip circle smaller than adiameter of a tooth bottom circle of the helical gear 13. Therefore, thehelical gear 13 is formed at a side, at which the pinion 14 ispositioned, with a side surface 13 a located at an outer periphery ofthe pinion 14. Parts of the pinion 14 between the gear parts 17, 17, 17are respectively formed as toothless parts 14 a, 14 a, 14 a. Forexample, the three toothless parts 14 a are formed with being equallyspaced in the circumferential direction.

As described above, the worm wheel 12 is made by integrally forming thehelical gear 13 and the pinion 14. Therefore, it is possible to reducethe number of components and to effectively transmit a driving force,which is to be transmitted from the motor 10 to the helical gear 13, tothe pinion 14, so that it is possible to reduce a size of the motor 10.

A cylinder 18 is coupled to the rear end portion of the case body 7. Thecylinder 18 is coupled with protruding rearwards from the case body 7.The cylinder 18 is made by integrally forming a piston support part 19and a coupling protrusion 20 protruding downwards from the pistonsupport part 19, for example, and a diameter of the piston support part19 is set greater than a diameter of the coupling protrusion 20.

The piston support part 19 has a substantially cylindricalcylinder-shaped part 21 extending in the front and rear direction and aclosing part 22 configured to close a rear opening of thecylinder-shaped part 21. An inner surface of the closing part 22 isformed as a closed surface 22 a.

An internal space 23 of the piston support part 19 includes a firstspace 24, which is a substantially rear half part, and a second space25, which is a substantially front half part.

Air inlet grooves 19 a, 19 a extending in the front and rear directionand spaced in the circumferential direction are formed in the secondspace 25 of the piston support part 19 (refer to FIGS. 4 to 6). The airinlet grooves 19 a, 19 a are located at 180° opposite sides, forexample. Meanwhile, the number of the air inlet groove 19 a is optional.When a plurality of air inlet grooves 19 a is provided, these air inletgrooves are preferably formed being equally spaced in thecircumferential direction.

Since the air inlet grooves 19 a, 19 a are formed in the second space 25of the piston support part 19, a part of the second space 25 where theair inlet grooves 19 a, 19 a are formed has a diameter slightly greaterthan that of the first space 24. A part of the second space 25 where theair inlet grooves 19 a, 19 a are not formed has the same diameter asthat of the first space 24. In the second space 25 of the piston supportpart 19, stepped surfaces 25 a, 25 a are respectively formed at boundaryportions between the first space 24 and the air inlet grooves 19 a, 19 a(refer to FIGS. 4 and 5).

The cylinder-shaped part 21 of the piston support part 19 is formed withan air inlet hole (not shown) from which an outside air is introducedinto the air inlet grooves 19 a, 19 a.

An internal space of the coupling protrusion 20 is formed as a deliverypath 20 a for delivering the high-pressure air towards the nozzle 6. Thecoupling protrusion 20 is coupled with a front end portion of the piping3.

The coupling protrusion 20 is continuous to the cylinder-shaped part 21and is located further forwards the closed surface 22 a of the closingpart 22 (refer to FIGS. 4 and 5). Therefore, a predetermined interval isformed between the closed surface 22 a and a rear end of the deliverypath 20 a, and a storage part 24 a, which is a part of the internalspace 23, is formed between the closed surface 22 a of the pistonsupport part 19 and the delivery path 20 a of the coupling protrusion20.

A piston 27 is movably supported to the piston support part 19 of thecylinder 18. The piston 27 has a substantially cylindrical column-shapedactuating part 28 of which a thickness in the front and rear directionis thin and a coupling part 29 protruding substantially forward from acentral portion of the actuating part 28. The actuating part 28 isformed with circular ring-shaped arrangement grooves 28 a, 28 a openingoutwards with being spaced in the front and rear direction. An outerdiameter of the actuating part 28 is slightly smaller than the diameterof the first space 24 of the piston support part 19. Therefore, a gap 26is formed between an outer peripheral surface of the actuating part 28and an inner peripheral surface of the piston support part 19 in thefirst space 24.

Seal parts 30, 30 are respectively arranged in the arrangement grooves28 a, 28 a. The seal part 30 is formed of, for example, an elasticallydeformable rubber or resin and an outer periphery thereof protrudesoutward from the outer peripheral surface of the actuating part 28.

The piston 27 is configured to reciprocate in the front and reardirection between a top dead center and a bottom dead center withrespect to the cylinder 18. At the top dead center, the actuating part28 is entirely positioned in the first space 21 a (refer to FIG. 4). Atthe bottom dead center, the seal parts 30, 30 are entirely positioned inthe second space 25 and a rear end portion of the actuating part 28 ispositioned in the first space 24 (refer to FIG. 5).

The seal parts 30, 30 of the piston 27 slide on an inner peripheralsurface of the cylinder 18 in the first space 21 a (refer to FIG. 4).Further, the seal parts 30, 30 slide on an inner peripheral surface of apart of the cylinder 18 other than the air inlet grooves 19 a, 19 a inthe second space 25, and are spaced away from an inner peripheralsurface of the piston support part 19 of the cylinder 18 at the partswhere the air inlet grooves 19 a, 19 a are formed (refer to FIG. 5).Therefore, at a state where the piston 27 is positioned at the bottomdead center, the air (outside air) introduced into the second space 25flows toward the first space 24 through the gap 26 along the steppedsurfaces 25 a, 25 a.

A rack 31 extending in the front and rear direction is coupled to thecoupling part 29 of the piston 27. The rack 31 is formed integrally withthe piston 27, for example.

The rack 31 is formed with a rack part 32 at a position close to a frontend thereof. The rack 31 is inserted into the insertion hole 9 d formedin the case body 7 and the rack part 32 is configured to be engageablewith the gear part 17 of the pinion 14 of the worm wheel 12.

Between the actuating part 28 of the piston 27 and an outer surface ofthe case body 7, an urging spring 33 is supported in the piston supportpart 19 of the cylinder 18. The urging spring 33 is, for example, acompression coil spring. The piston 27 and the rack 31 are urgedrearward by the urging spring 33.

In the meantime, regarding a moving direction of the piston 27, a reardirection in which the air is to be delivered is a delivery direction,and a front direction, which is an opposite direction to the deliverydirection, is a force accumulation direction. The force accumulationdirection is a direction in which the piston 27 is to move against anurging force of the urging spring 33. As the piston 27 is moved in theforce accumulation direction, a moving force in the delivery direction,which is to be applied to the piston 27 by the urging force of theurging spring 33, increases.

<Operation of Foreign Matter Removal Device>

In the below, an operation of the foreign matter removal device 1 isdescribed (refer to FIGS. 7 to 10).

First, an initial state before high-pressure air is delivered isdescribed (refer to FIG. 7).

At the initial state, the piston 27 is positioned at the rear in themoving direction, and the rack 31 is positioned at a state where therack part 32 can engage with the gear parts 17, 17, 17 of the pinion 14.

When the driving of the motor 10 starts at the initial state and adriving force of the motor 10 is transmitted to the worm wheel 12through the worm 11, the gear part 17 of the pinion 14 is engaged withthe rack part 28 of the rack 31 (refer to FIG. 8). Therefore, as thepinion 14 is rotated, the rack 31 is moved in the force accumulationdirection against the urging force of the urging spring 33.

When the rack 31 is moved in the force accumulation direction as thepinion 14 is rotated, the engaged state between the gear part 17 and therack part 32 is released at a predetermined position (refer to FIG. 9).The position at which the engaged state between the gear part 17 and therack part 32 is released is the bottom dead center of the piston 27. Atthe state where the piston 27 is positioned at the bottom dead center,the air (outside air) introduced into the second space 25 flows towardsthe first space 24 through the gap 26 along the stepped surfaces 25 a,25 a, as described above.

When the piston 27 is moved to the bottom dead center, the engaged statebetween the gear part 17 and the rack part 32 is released, so that thepiston 27 is moved in the delivery direction at higher speed than amoving speed in the force accumulation direction by the urging force ofthe urging spring 33 (refer to FIG. 10) and the air introduced into thefirst space 24 from the second space 25 is delivered from the firstspace 24 towards the nozzle 6 of the nozzle unit 2 through the deliverypath 20 a of the coupling protrusion 20. At this time, since thecylinder 18 has a configuration where the diameter of the couplingprotrusion 20 is smaller than that of the piston support part 19, theair delivered from the first space 24 through the delivery path 20 a iscompressed into high-pressure air, which is then delivered from thepiping 3 towards the nozzle 6. Then, the high-pressure air is injectedfrom the nozzle 6 and blown to the lens part 101 of the imaging unit ofthe in-vehicle camera 100.

During the movement of the piston 27 in the delivery direction by theurging force of the urging spring 33, the high-pressure air is deliveredfrom the coupling protrusion 20 towards the nozzle 6 and the deliverypath 20 a of the coupling protrusion 20 is closed by the seal parts 30,30 of the piston 27. When the delivery path 20 a is closed by the sealparts 30, 30, a part of the air in the internal space 23 pressed by theactuating part 28 of the piston 27 is confined in the storage part 24 a.The confined air is pressed by the actuating part 28, so that thecompressed air is generated.

Like this, when the piston 27 is moved in the delivery direction, theair confined in the storage part 24 a becomes the compressed air, sothat the compressed air functions as an air spring and the movement ofthe piston 27 in the delivery direction is restrained. Therefore, thepiston 27 is stopped at a position immediately before the actuating part28 is contacted to the closed surface 22 a by the compressed air, andthe stop position is the top dead center of the piston 27.

In the meantime, at the state where the piston 27 is moved in thedelivery direction by the urging force of the urging spring 33 and isthen stopped, the rear seal part 30 close to the closed surface 22 a maybe positioned at the rear of the rear end of the delivery path 20 a.However, since the piston 27 is provided with the two seal parts 30, 30spaced in the front and rear direction, even when the rear seal part 30is positioned at the rear of the rear end of the delivery path 20 a, afront end of the front seal part 30 is positioned further forwards afront end of the delivery path 20 a.

Therefore, the delivery path 20 a is closed by the seal parts 30, 30, sothat it is possible to prevent the air introduced into the internalspace 23 from being unnecessarily discharged from the delivery path 20a.

The high-pressure air injected from the nozzle 6 is blown to the lenspart 101, so that foreign matters such as dust, mud and water dropletsattached to the lens part 101 are blown away and the contamination ofthe lens part 101 is thus addressed.

As described above, in the foreign matter removal device 1, the diameterof at least a part of the second space 25 of the cylinder 18 is setgreater than that of the first space 24. Further, when the piston 27 ismoved to the bottom dead center, the seal parts 30, 30 are entirelylocated in the second space 25 and the air introduced into the secondspace 25 flows from the second space 25 towards the first space 24.

Therefore, even when the foreign matters such as dust and mud enter thenozzle 6 and an injection port of the nozzle 6 is thus clogged by theforeign matters, the air is securely introduced into the first space 24of the cylinder 18 and the foreign matters clogging the nozzle 6 areblown away by the high-pressure air introduced into the first space 24and delivered by the piston 27. Therefore, the clogging of the nozzle 6due to the foreign matters can be addressed, so that it is possible tosecure the favorable injection state of the high-pressure air from thenozzle 6.

The above-described reciprocating movement of the piston 27 between thetop dead center and the bottom dead center is performed by using anengagement between the gear part 17 of the pinion 14 and the rack part31 of the rack 31 and a release thereof as one cycle, and the movementof the piston 27 in the delivery direction is performed by the presenceof the toothless part 14 a of the pinion 14.

Therefore, since the piston 27 is moved in the delivery direction by thepresence of the toothless part 14 a, there is no need to provide adedicated mechanism for moving the piston 27 in the delivery direction.As a result, the size reduction by the simplification of the mechanismof the foreign matter removal device 1 can be achieved.

Also, since the foreign matter removal device 1 has the configurationwhere the gear parts 17, 17, 17 are provided at three positions spacedin the circumferential direction of the pinion 14 and the threetoothless parts 14 a, 14 a, 14 a are formed, the reciprocating movementof the piston 27 between the top dead center and the bottom dead centeris performed three times (three cycles) during one rotation of thepinion 14.

Therefore, the number of times of injection of the high-pressure airfrom the nozzle 6 during one rotation of the pinion 14 is increased, sothat it is possible to improve the injection efficiency in the foreignmatter removal device 1.

BRIEF SUMMARY

As described above, in the foreign matter removal device 1, the cylinder18 is provided with the piston support part 19 configured to support thepiston 27 and the coupling protrusion 20 having the delivery path 20 afor delivering the high-pressure air, and the coupling protrusion 20 islocated further towards the force accumulation direction than the closedsurface 22 a of the piston support part 19.

Also, when the piston 27 is moved in the delivery direction, a part ofthe air in the cylinder 18 is compressed and the compressed air is thusgenerated, and the compressed air is confined in the storage part 24 a,which is an end portion in the cylinder 18 in the delivery direction.

Therefore, when the piston 27 is moved in the delivery direction, thecompressed air is interposed between the piston 27 and the end portionof the cylinder 18 in the delivery direction. Thereby, contact betweenthe piston 27 and the end portion of the cylinder 18 in the deliverydirection is avoided, so that it is possible to prevent occurrence of anabnormal sound and damages and failures of the piston 27 and thecylinder 18.

Also, since the driving force of the motor 10 is transmitted to thepiston 27 via the worm 11 and the worm wheel 12, a reduction mechanismwhere a large reduction ratio is to be obtained by a simple mechanismhaving a small number of components is configured by using the worm 11and the worm wheel 12. Also, it is possible to secure high conversionefficiency of the moving force of the piston 27 to the driving force ofthe motor 10 by the simple mechanism.

Also, since the worm 11 is used as the main driving gear and the wormwheel 12 is used as the driven gear, a reduction mechanism where a largereduction ratio is to be obtained by a simple mechanism is configuredand high conversion efficiency of the moving force of the piston 27 tothe driving force of the motor 10 can be secured by a simpler mechanism.

Modified Embodiments of Moving Mechanism

In the below, each modified embodiment of the moving mechanism isdescribed (refer to FIGS. 11 to 13). In the meantime, shapes anddimensions of case bodies 7A, 7B, 7C in which moving mechanisms ofmodified embodiments are arranged are changed with respect to the casebody 7 in accordance with respective structures of the moving mechanismsand arrangement spaces 9A, 9B, 9C corresponding to the respectivestructures are formed in the case bodies.

First, a moving mechanism 8A of a first modified embodiment is described(refer to FIG. 11).

The moving mechanism 8A includes a motor 10A and a pinion 14A.

The motor 10A has a main body part 10 a and a motor shaft 10 b. Themotor shaft 10 b is arranged in a direction orthogonal to the movingdirection of the rack 31.

The pinion 14A is fixedly coupled to the motor shaft 10 b and functionsas the main driving gear. The pinion 14A has the same configuration asthe pinion 14 and includes the annular part 16 and the gear parts 17,17, 17, and parts of the pinion between the gear parts 17, 17, 17 arerespectively formed as the toothless parts 14 a, 14 a, 14 a.

The rack part 32 of the rack 31 is formed as the driven gear, and therack part 32 is configured to be engageable with the gear part 17 of thepinion 14A.

In the configuration where the moving mechanism 8A is provided, when themotor 10A starts to drive, the gear part 17 of the pinion 14A is engagedwith the rack part 32 of the rack 31 and the rack 31 is moved in theforce accumulation direction against the urging force of the urgingspring 33.

When the engaged state between the gear part 17 and the rack part 32 isreleased at a predetermined position, the piston 27 is moved in thedelivery direction at higher speed than the moving speed in the forceaccumulation direction by the urging force of the urging spring 33 andthe air in the first space 24 is injected from the nozzle 6, as thehigh-pressure air.

In the moving mechanism 8A, since the driving force of the motor 10A istransmitted from the pinion 14A coupled to the motor shaft 10 b to therack 31, the structure is simple and the number of components of theforeign matter removal device 1 and the size thereof can be reduced.

Subsequently, a moving mechanism 8B of a second modified embodiment isdescribed (refer to FIG. 12).

The moving mechanism 8B has a motor 10B, a transmission gear 34 and anactuating gear 35.

The motor 10B has a main body part 10 a and a motor shaft 10 b. Themotor shaft 10 b is arranged in a direction orthogonal to the movingdirection of the rack 31.

The transmission gear 34 is a spur gear, is fixedly coupled to the motorshaft 10 b and functions as the main driving gear.

The actuating gear 35 functions as the driven gear, and is made byintegrally forming a spur gear 36 and a pinion 14B protruding laterallyfrom a central portion of the spur gear 36. The actuating gear 35 issupported at a central portion thereof to a support shaft part 7 a of acase body 7B via the bearing 15.

The spur gear 36 is engaged with the transmission gear 34.

The pinion 14B is arranged concentrically with the spur gear 36 and hasthe same configuration as the pinion 14.

The rack 31 is configured so that the rack part 32 is engageable withthe gear part 17 of the pinion 14B.

In the configuration where the moving mechanism 8B is provided, when themotor 10B starts to drive, the driving force of the motor 10B istransmitted to the actuating gear 35 via the transmission gear 34, sothat the gear part 17 of the pinion 14B is engaged with the rack part 32of the rack 31 and the rack 31 is moved in the force accumulationdirection against the urging force of the urging spring 33.

When the engaged state between the gear part 17 and the rack part 32 isreleased at a predetermined position, the piston 27 is moved in thedelivery direction at higher speed than the moving speed in the forceaccumulation direction by the urging force of the urging spring 33 andthe air in the first space 24 is injected from the nozzle 6, as thehigh-pressure air.

In the moving mechanism 8B, since the driving force of the motor 10B istransmitted to the rack 31 via the transmission gear 34 (the spur gear)and the actuating gear 35 having the spur gear 36, directions ofrotation axes of the transmission gear 34 and the actuating gear 35 arethe same.

Therefore, it is possible to reduce an arranging space of the movingmechanism 8B. Also, the structure is simple and the number of componentsof the foreign matter removal device 1 and the size thereof can bereduced.

Subsequently, a moving mechanism 8C of a third modified embodiment isdescribed (refer to FIG. 13).

The moving mechanism 8C is configured by a solenoid 37.

The solenoid 37 includes a driving shaft 38 extending in the front andrear direction and a coil 39 in which the driving shaft 38 is inserted.The driving shaft 38 is an iron core, for example.

In the configuration where the moving mechanism 8C is provided, the rack31 is not provided and the driving shaft 38 is coupled to the couplingpart 29 of the piston 27.

In the configuration where the moving mechanism 8C is provided, when thecoil 39 is energized and thus the solenoid 37 starts to drive, thedriving shaft 38 and the piston 27 are integrally moved in the forceaccumulation direction against the urging force of the urging spring 33.

When the energization to the coil 39 is stopped at a predeterminedposition, the driving shaft 38 and the piston 27 are moved in thedelivery direction at higher speed than the moving speed in the forceaccumulation direction by the urging force of the urging spring 33 andthe air in the first space 24 is injected from the nozzle 6, as thehigh-pressure air.

In the moving mechanism 8C, since the driving shaft 38 of the solenoid37 is coupled to the piston 27 and the driving force is transmitted tothe piston 27, the structure is simple and the number of components ofthe foreign matter removal device 1 and the size thereof can be reduced.

First Illustrative Embodiment of Removal Drive Device

In the below, a removal drive device of an illustrative embodiment isdescribed with reference to the drawings.

First, a first illustrative embodiment of the removal drive deviceconfigured to drive the foreign matter removal device 1 is describedwith reference to FIGS. 14 to 16.

FIG. 14 is a block diagram of a removal drive device 50. The removaldrive device 50 is a device configured to supply driving current to themotor 10.

The removal drive device 50 has four terminals T1, T2, T3, T4, as aconnection terminal to an outside of the device.

The terminal T1 is connected to a power supply line 61. The power supplyline 61 is a line to which a power supply voltage V1 is to be suppliedvia a switch 90. The switch 90 is an on/off switch of a specific powersupply system in the vehicle. For example, the power supply voltage is12V, and the switch 90 becomes on by a signal S1, which is to be outputas a gear position of the vehicle falls within a reverse range.Specifically, the power supply line 61 is a line of a rear lamp powersupply system. Therefore, in the removal drive device 50 of the firstillustrative embodiment, when the vehicle falls within the reverse rangeand thus a rear lamp turns on, the power supply voltage V1 of 12V issupplied to the terminal T1.

The terminal T2 is connected to a ground (for example, a vehicle bodyground) by a ground line 62. The terminal T3 is connected to a positiveelectrode of the motor 10, and the terminal T4 is connected to anegative electrode of the motor 10. That is, the removal drive device 50supplies the driving current between the terminals T3, T4, so that themotor 10 of the foreign matter removal device 1 drives and theabove-described foreign matter removal operation is thus executed.

The removal drive device 50 is provided with a power supply filter 51,an operation setting unit 52 and a motor driver 53.

The power supply filter 51 is provided so as to protect a circuit in theremoval drive device 50 from electric surge and noise, therebypreventing a malfunction.

The motor driver 53 is configured to supply the driving current to themotor 10 of the foreign matter removal device 1 and to enable theforeign matter removal device 1 to execute the foreign matter removaloperation. In the first illustrative embodiment, the terminal T1 and theterminal T3 are connected, so that the power supply voltage V1 from thepower supply line 61 is applied to the positive electrode of the motor10 at the state of the reverse range. The motor driver 53 is configuredto generate the driving current by connecting the terminal T4 (thenegative electrode of the motor 10) to the ground (the terminal T2).

The motor driver 53 is configured to generate the driving current for atime period that is indicated by a signal Sm from the operation settingunit 52.

The operation setting unit 52 is configured to control a time period forwhich the motor driver 53 is to generate the driving current by thesignal Sm.

Specifically, when the vehicle falls within the reverse range, theswitch 90 becomes on and the power supply voltage V1 is applied to theterminal T1, the operation setting unit 52 performs the control so thatthe driving current is supplied to the motor 10 by the motor driver 53,for a first predetermined time. That is, when the power supply voltageV1 is applied, the foreign matter removal operation is performed in theforeign matter removal device 1 for the first predetermined time.

Also, the operation setting unit 52 is configured to control the motordriver 53 so that the driving current is not to be supplied to the motor10 for a second predetermined time after the power supply voltage V1 isapplied to the terminal T1, instead of executing the foreign matterremoval operation immediately after the power supply voltage V1 isapplied.

A driving operation is described with reference to FIGS. 15A and 15B. Asshown in FIG. 15A, it is assumed that a terminal voltage of the terminalT1 becomes the power supply voltage V1 at predetermined time. Theoperation setting unit 52 does not enable the motor driver 53 to supplythe driving current, immediately in response to the change in voltage ofthe terminal T1. Specifically, for second predetermined time tm (forexample, about 0.2 second), the operation setting unit does not raisethe signal Sm. After the second predetermined time tm elapses, theoperation setting unit sets the signal Sm to an H level for firstpredetermined time td (for example, about 1.8 seconds) and enables themotor driver 53 to generate the driving current between the terminalsT3, T4 for the first predetermined time. Therefore, for the firstpredetermined time td, the motor 10 operates, so that the foreign matterremoval operation is executed. That is, for about 1.8 seconds, forexample, the motor 10 rotates the worm 11, so that the piston 27reciprocates several times and the high-pressure air is injected severaltimes, as can be understood from the descriptions of FIGS. 2 to 5.

In the meantime, the power supply voltage V1 may be instantaneouslyapplied to the terminal T1. For example, a case where the driveroperates a shift lever to pass the reverse range may be exemplified. Theshift lever falls instantaneously within the reverse range and theswitch 90 becomes on, so that the power supply voltage V1 is temporarilyapplied to the terminal T1. This aspect is shown in FIG. 15B.

However, when a time period for which the terminal T1 becomes the powersupply voltage V1 is shorter than the second predetermined time tm, theoperation setting unit 52 does not raise the signal Sm. For this reason,the motor driver 53 does not supply the driving current to the motor 10.

An example of a specific circuit of the removal drive device 50 forimplementing the above operations is shown in FIG. 16.

In the removal drive device 50, the terminal T1 is connected to theterminal T3 for a reverse-current protecting diode D1. Thereby, thepower supply voltage V1 is applied from the terminal T3 to the positiveelectrode-side of the motor 10. Therefore, the negative electrode-side(terminal T4) of the motor 10 is connected to the ground, so that thedriving current flows through the motor 10.

Meanwhile, in FIG. 16 (and FIGS. 14, 17 and 19), the ground symbols inthe removal drive device 50 are all connected to the terminal T2 in theremoval drive device 50, and the terminal T2 is connected to a vehiclebody ground by a wiring and the like.

The power supply filter 51 includes capacitors C1, C2 and a diode D2.The surge protection is made by the capacitors C1, C2 connected inseries between the terminal T1 and the ground.

The motor driver 53 is configured by a motor driver IC and is a circuitconfigured to connect the terminal T4 to the ground (terminal T2) inresponse to an input of the signal Sm.

The motor driver 53 is configured to perform a motor driving operationby an N-channel MOS-FET 53 a and a resistance R7, in accordance with thesignal Sm.

The MOS-FET 53 a has a drain connected to the terminal T4 and a sourceconnected to the ground (terminal T2). A gate of the MOS-FET 53 a issupplied with the signal Sm via the resistance R7. A clamp circuitincluding a diode D4 and a Zener diode ZD2 is inserted between the drainand the gate of the MOS-FET 53 a.

The MOS-FET 53 a of the motor driver 53 is configured to be on/off bythe signal Sm from the operation setting unit 52. When the MOS-FET 53 abecomes on, the driving current flows through the motor 10. That is, theMOS-FET 53 a functions as a driving switch of the motor 10.

Resistances R1 to R6, capacitors C3 to C8, a diode D3, a Zener diode ZD1and comparators (operational amplifiers) A1, A2 are connected as shown,so that the operation setting unit 52 is configured. The operations ofthe operation setting unit 52 are described, as follows.

First, the first predetermined time td is defined by the resistances R1,R2, R3, the capacitor C3 and the comparator A1. Meanwhile, in the showncircuit, actually, (td+tm) is defined by an output of the comparator A1and a time period of the second predetermined time tm is masked at thecomparator A2 provided at a rear end.

A cathode-side of the diode D2 becomes the power supply line 65 of thecomparators A1, A2. The resistance R1 and the capacitor C3 are connectedin series between the power supply line 65 and the ground (terminal T2).Therefore, the capacitor C3 is charged from a point of time at which thesupply of the power supply voltage V1 to the terminal T1 starts. Avoltage associated with an amount of charge of the capacitor C3 is inputto a (−) terminal of the comparator A1.

Also, the resistances R2, R3 are connected in series between the powersupply line 65 and the ground, and a voltage divided at the resistancesR2, R3 is input to a (+) terminal of the comparator A1, as a referencevoltage.

Therefore, for a time period from the point of time at which the powersupply voltage V1 is applied to the terminal T1 to a point of time atwhich the terminal voltage of the capacitor C3 associated with theamount of charge thereof reaches a predetermined value, i.e., thedivided voltage by the resistances R2, R3, the output of the comparatorA1 becomes an H level, and when the terminal voltage of the capacitor C3exceeds the divided voltage by the resistances R2, R3, the output of thecomparator A1 becomes an L level. Constants of the respective elementsare set so that a timing at which the output is dropped to the L levelis a timing beyond the first and second predetermined time (tm+td) ofFIGS. 15A and 15B.

Then, the second predetermined time tm is set by the resistance R4, thecapacitors C6 and the comparator A2. An output of a time constantcircuit configured by the resistance R4 and the capacitor C6 is an inputof a (+) terminal of the comparator A2. Also, the voltage divided at theresistances R2, R3 is input to the (−) terminal of the comparator A1, asthe reference voltage.

In this case, since the output of the comparator A1 is supplied to thecomparator A2 via the time constant circuit, even though the output ofthe comparator A1 becomes the H level at the point of time at which thepower supply voltage V1 is applied to the terminal T1, the input voltageof the (+) terminal of the comparator A2 does not immediately reach thereference voltage. Therefore, immediately after the power supply voltageV1 is applied to the terminal T1, the output of the comparator A2becomes the L level. Thereafter, when the input voltage of the (+)terminal of the comparator A2 rises and exceeds the reference voltage,the output of the comparator A2 becomes the H level. The referencevoltage and the time constant are set so that the time period up to nowis the second predetermined time tm of FIGS. 15A and 15B.

The output of the comparator A2 is stabilized by the capacitor C8 and isvoltage-clipped by the Zener diode ZD1. A voltage value obtained at oneend of the resistance R6 becomes the signal Sm for the motor driver 53.

In the motor driver 53, for the time period of the H level of the signalSm, the MOS-FET 53 a becomes on, so that the terminal T4 is connected tothe terminal T2 (ground).

Therefore, as shown in FIG. 15A, as the power supply voltage V1 issupplied to the terminal T1, the signal Sm becomes the H level for thefirst predetermined time td after the second predetermined time tmelapses, and the driving current is supplied to the motor 10 for thecorresponding time period, so that the foreign matter removal operationis performed by the foreign matter removal device 1.

Also, as shown in FIG. 15B, when the power supply voltage V1 is appliedonly for a time period that does not reach the second predetermined timetm, since the output (signal Sm) of the comparator A2 is not the Hlevel, the driving current is not supplied to the motor 10.

As described above, the removal drive device 50 of the firstillustrative embodiment includes the terminal T1 connected to the powersupply line in the vehicle, the terminal T2 connected to the ground linein the vehicle, the motor driver 53 configured to supply the drivingcurrent to the motor 10 of the foreign matter removal device 1 and toenable the foreign matter removal device 1 to execute the foreign matterremoval operation, and the operation setting unit 52 configured toinstruct the motor driver 53 to supply the driving current to the motor10 only for the first predetermined time td as the power supply voltageV1 is applied to the terminal T1 at the state where the terminal T2 isconnected to the ground.

That is, when the voltage between the power supply voltage V1 and theground is applied between the terminals T1, T2, which is a trigger, theoperation setting unit 52 sets the foreign matter removal drive time(first predetermined time Td). Thereby, in the minimum wiringconfiguration of only the connection between the power supply line andthe ground line without providing an input system such as a dedicatedcontrol line, it is possible to execute the foreign matter removal onthe imaging surface (the lens part 101) and the like of the in-vehiclecamera 100 at the appropriate time period.

Also, only for the first predetermined time period Td, the foreignmatter removal operation is performed, so that it is not necessary toexcessively perform the foreign matter removal operation and theefficient operation is thus performed. Also, there is a merit that theoperation control can be performed only by the power supply and theground wiring.

Also, a dedicated control line is not required, so that it is possibleto apply the above configuration to a variety of vehicles and to improvethe degree of freedom of wiring.

Also, the example where the power supply line 61, to which the powersupply voltage is supplied as the vehicle falls within the reverserange, is connected to the terminal T1 has been described. When theforeign matter removal device 1 sets the rear camera (the in-vehiclecamera 100) of the vehicle as a target of the foreign matter removal, itis preferably to execute the foreign matter removal upon operation startof the rear camera. The terminal T1 is connected to the power supplyline 61, to which the power supply voltage V1 is supplied as the vehiclefalls within the reverse range, so that it is possible to start theforeign matter removal operation upon start of rear traveling of thevehicle, i.e., upon operation start of the in-vehicle camera 100, whichis the rear camera.

Meanwhile, in general, the in-vehicle camera 100 (rear camera) and amonitor screen configured to display a captured image of the in-vehiclecamera are activated and start an image display at about two secondsafter the driver moves the shift lever to the reverse range. Asdescribed above, when the second predetermined time period tm is set to0.2 second and the first predetermined time period Td is set to 1.8seconds, the foreign matter removal is completed until the monitorscreen display starts after the shift to the reverse range. Thereby,regarding the foreign matter removal on the imaging surface of the rearcamera, the foreign matter removal operation is performed at the optimaltiming immediately before performing the imaging and monitoring.

In other words, the foreign matter removal is not executed at a point oftime at which the corresponding operation is not required so much, andit is possible to optimize the timing of the foreign matter removaloperation and to implement the efficient foreign matter removaloperation.

Also, the operation setting unit 52 controls the motor driver 53 not tosupply the driving current to the motor 10 for the second predeterminedtime Tm after the power supply voltage is applied to the terminal T1 atthe state where the terminal T2 is connected to the ground.

Thereby, for example, when the shift lever operation of the driverpasses the reverse range or when the power supply voltage V1 is suppliedto the terminal T1 for only a moment by any trigger, a useless foreignmatter removal operation is not performed.

Second Illustrative Embodiment of Removal Drive Device

A configuration of the removal drive device 50 of a second illustrativeembodiment is shown in FIG. 17. The same parts as FIG. 14 are denotedwith the same reference numerals, and the descriptions thereof areomitted.

In the second illustrative embodiment, a voltage conversion unit 54 isprovided between the terminal T1 and the power supply filter 51 (or theterminal T3). The voltage conversion unit 54 is a well-known buck-boostDC/DC converter or the like and is configured to perform voltageconversion in accordance with a voltage to be applied to the terminalT1.

In FIG. 17, the power supply line 61 to which the terminal T1 isconnected is supplied with the power supply voltage V1 via the switch90.

In the meantime, the power supply voltage V1 may be a 24V power supply,a 6V power supply or a 12V power supply like the first illustrativeembodiment, for example. For example, when the vehicle is a truck and apower supply line of a 24V battery is connected to the removal drivedevice 50, the power supply voltage V1 is 24V. Also, when the powersupply is commonly used for the in-vehicle camera 100 and the removaldrive device 50, if the in-vehicle camera 100 uses a 6V power supply,the power supply voltage V1 is 6V.

A signal S1 for turning on or off the switch 90 is a signalcorresponding to a power supply system to be connected. For example, inthe case of a power supply system for the in-vehicle camera 100, thesignal is a signal for turning on the switch 90 at a timing at which thein-vehicle camera 100 becomes on. In addition, the signal may be asignal for turning on the switch 90 in response to the shift to thereverse range, like the first illustrative embodiment, or a signal forturning on the switch 90 by ignition-on.

Since the type of the vehicle on which the removal drive device 50 is tobe mounted and the wiring specification are diverse, it is favorable ifthe removal drive device 50 can cope with the connections to the diversepower supply lines. Therefore, the voltage conversion unit 54 isprovided, as shown in FIG. 17.

When the removal drive device 50 uses a 12V power supply, the voltageconversion unit 54 operates, as follows.

When the power supply voltage V1 to the terminal T1 is 24V, the inputvoltage 24V is dropped to 12V, which is then output.

When the power supply voltage V1 to the terminal T1 is 12V, the inputvoltage 24V is output as it is, without converting the same.

When the power supply voltage V1 to the terminal T1 is 6V, the inputvoltage 6V is boosted to 12V, which is then output.

Like this, the voltage conversion unit 54 operates, in accordance withthe voltage value of the power supply voltage V1 applied to the terminalT1. The output voltage (for example, 12V) of the voltage conversion unit54 is supplied to the terminal T3, which becomes a driving voltage forsupplying the driving current to the motor 10 and a power supply voltagefor operating the operation setting unit 52.

Like this, the voltage conversion unit 54 configured to generate thedriving voltage of the motor 10 by boosting or dropping the power supplyvoltage V1 to be supplied to the terminal T1 is provided, so that it ispossible to cope with the diverse power supply systems even though thedriving voltage for the motor 10 and the configuration for drive timecontrol of the operation setting unit 52 are designed in conformity tothe specific power supply voltage of 12V, for example.

Therefore, it is possible to mount the removal drive device 50 to avariety of types of the vehicle and to increase the degree of freedom ofthe power supply line to be connected.

Third Illustrative Embodiment of Removal Drive Device

In the first and second illustrative embodiments, the switch 90 isprovided for the power supply line 61, and when the power supply voltageV1 is supplied to the terminal T1, the motor 10 is driven. This aspectis shown in FIG. 18A.

The applying of the voltage V1 to the terminal T1 is controlled by theswitch 90, and the terminal T2 is normally connected to the ground. Whenthe voltage is applied to the terminal T1, the signal Sm becomes the Hlevel only for the first predetermined time td after the secondpredetermined time tm elapses, and the motor 10 is operated for thecorresponding time period.

In contrast, the motor driving operation may be performed by normallyapplying the voltage to the terminal T1 and controlling the connectionof the terminal T2 to the ground.

FIG. 19 shows a configuration example of a third illustrativeembodiment. In FIG. 19, the configuration of the removal drive device 50is the same as the first illustrative embodiment (FIG. 14).Alternatively, the voltage conversion unit 54 may be provided, like thesecond illustrative embodiment (FIG. 17). In FIG. 19, the connectionstates of the terminals T1, T2 are different.

The terminal T1 is connected to the power supply line 61 of the powersupply voltage V1. The switch 90 shown in FIG. 14 is not interposed. Forexample, when the power supply line 61 is an ignition-type power supplyline to which a battery power supply voltage is to be supplied byignition-on, the voltage of the terminal T1 is normally the power supplyvoltage V1 (the vehicle is at an ignition-on state). FIG. 18B depicts astate where the voltage of the terminal T1 is normally the power supplyvoltage V1.

On the other hand, the terminal T2 is not directly connected to theground and is connected to a terminal T91 of the ECU 91 of the vehiclevia a line 62A, for example.

In the ECU 91, for example, a resistance R100 and a collector and anemitter of a bipolar transistor serving as a switch element Q1 areconnected in series between a power supply voltage V2 and the ground,and a connection point thereof is connected to the terminal T91. A baseof the bipolar transistor serving as the switch element Q1 is suppliedwith a signal S3 for on/off control, based on control processing of theECU 91. In the meantime, the power supply voltage V2=V1, for example.

In this case, when the switch element Q1 is off, the voltage of theterminal T2 becomes a predetermined voltage (=V2). On the other hand,when the switch element Q1 becomes on, the voltage of the terminal T2becomes a ground potential. FIG. 18B depicts an aspect in which as theswitch element Q1 becomes on and off by the signal S3, the voltage ofthe terminal T2 changes. That is, the terminal T2 is selectivelyconnected to a predetermined voltage point and the ground.

As shown in FIG. 18B, the operation setting unit 52 generates the signalSm to control the motor driver 53. The specific circuit example of theoperation setting unit 52 has been described with reference to FIG. 16.In the circuit of FIG. 16, when the voltage between the power supplyvoltage V1 and the ground is applied between the terminals T1, T2, whichis a trigger, the operation setting unit 52 sets the foreign matterremoval drive time (first predetermined time Td) and start timing (afterthe second predetermined time Tm). That is, the voltage between thepower supply voltage V1 and the ground is applied between the terminalsT1, T2, the comparators A1, A2 and the peripheral circuit thereofoperate, as described above.

Therefore, as the power supply voltage V1 is applied to the terminal T1at the state where the terminal T2 is connected to the ground, thedriving current is supplied to the motor driver, like the firstillustrative embodiment. However, also in the case where the terminal T2becomes the ground potential from the potential of the predeterminedvoltage point at a state where the power supply voltage V1 is applied tothe terminal T1, the same operation is performed, as shown in FIG. 19.That is, after the second predetermined time tm elapses from a point oftime at which the terminal T2 becomes the ground potential, the signalSm becomes the H level for the first predetermined time td and thedriving current is supplied to the motor 10 by the motor driver 53 forthe corresponding time period (refer to the signal Sm in FIG. 18B).

Like the third illustrative embodiment, the terminal T1 may be directlyconnected to the power supply line 61 to which the power supply voltageV1 is to be supplied, and the terminal T2 may be selectively connectedto the predetermined voltage point and the ground. In this case, whenthe terminal T2 becomes the ground potential from the potential of thepredetermined voltage point at the state where the power supply voltageV1 is applied to the terminal T1, the operation setting unit 52 controlsthe motor driver 53 to supply the driving current to the motor 10.

That is, the operation of the removal drive device 50 can executed bythe control at the ground line-side, too, so that it is possible toimprove the degree of freedom of the power supply line wiring to theterminal T1.

For example, even when the wiring is made so that the power supplyvoltage V1 is normally to be supplied to the terminal T1 atpredetermined conditions such as ignition-on, the terminal T2 isselectively connected to the predetermined voltage point and the ground,so that it is possible to perform the foreign matter removal operationat the appropriate timing and for the appropriate time period.

Modified Embodiments

The configurations and connection aspects of the present invention arenot limited to the above illustrative embodiments, and a variety ofmodified embodiments are possible.

For example, in the first illustrative embodiment, when the vehiclefalls within the reverse range, the power supply voltage V1 is suppliedto the terminal T1. However, a case where the switch 90 becomes on atother conditions and the power supply voltage V1 is supplied to theterminal T1 is also considered.

For example, it is considered to perform the foreign matter removal whendirt is detected on the lens part 101 of the in-vehicle camera 100. Forinstance, the ECU 91 or image processing unit mounted on the vehicletimely analyzes a captured image of the in-vehicle camera 100. Forexample, it is possible to estimate a state where water droplets anddirt are attached, from a distribution, an amount, a contrast and thelike of edge components on the image. When a dirtiness state isdetermined by the image analysis, the control of turning on the switch90 of FIG. 14 (or turning on the switch element Q1 of FIG. 19) may beperformed to execute the foreign matter removal, for example.

Also, a configuring of turning on the switch 90 (switch element Q1) inaccordance with a driver's operation may be added.

Also, the example where the foreign matter removal device 1 is appliedas the foreign matter removal device 1 of the in-vehicle camera 100 hasbeen exemplified. However, the foreign matter removal device 1 can alsobe widely applied as a device for removing foreign matters of therespective parts provided for the vehicle, which are objects of whichforeign matters are to be removed, such as a vehicle lamp, a window, amirror, a collision prevention sensor, and the like. Therefore, theremoval drive device 50 of the present invention can be applied as adevice for driving a variety of the foreign matter removal devices 1.Also, it is possible to set the foreign matter removal timing, incorrespondence to a place to which the foreign matter removal is to beapplied.

Also, the target to which the present invention is to be applied is notparticularly limited inasmuch as the target is a device to be usedoutdoor. For example, the present invention can be applied to a cameraand other devices that are to be attached to an airplane, a train, arobot, an outdoor installation, a building and the like with beingexposed outside.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

The invention claimed is:
 1. A foreign matter removal device comprising:a cylinder in which air is introduced; a piston movably supported to thecylinder and configured to deliver the air introduced into the cylinderas high-pressure air; a nozzle configured to inject the high-pressureair delivered by the piston towards an object to be washed; an urgingspring configured to urge the piston, and a moving mechanism configuredto move the piston to a predetermined position by applying a movingforce to the piston, wherein regarding a moving direction of the piston,a direction in which the high-pressure air is to be delivered is adelivery direction and an opposite direction to the delivery directionis a force accumulation direction, wherein the piston is configured tomove in the force accumulation direction by the moving mechanism and tomove in the delivery direction by an urging force of the urging springin response to release of the moving force applied by the movingmechanism at the predetermined position, wherein the cylinder isprovided with a piston support part configured to movably support thepiston and a coupling protrusion having a delivery path, which continuesto the piston support part and is configured to deliver thehigh-pressure air towards the nozzle, wherein an inner surface of an endportion of the piston support part in the delivery direction is formedas a closed surface, wherein the delivery path is located furthertowards the force accumulation direction than the closed surface,wherein the moving mechanism comprises a main driving gear configured torotate by a driving force of a motor and a driven gear configured toengage with the main driving gear and to rotate in association withrotation of the main driving gear, wherein the driving force of themotor is to be transmitted to the piston via the main driving gear andthe driven gear, wherein a rack coupled to the piston is provided,wherein the driven gear is provided with a pinion that is to be engagedwith the rack, wherein a gear part is provided at a part of an outerperiphery of the pinion, wherein a part of the outer periphery of thepinion where the gear part is not provided is formed as a toothlesspart, wherein a plurality of the gear parts is formed with being spacedin a circumferential direction, and wherein when an opposed surface ofthe piston facing the closed surface is moved in the delivery directionaway from the delivery path, a space closed by the inner surfaceincluding the closed surface of the piston support part and the opposedsurface of the piston is formed.
 2. The foreign matter removal deviceaccording to claim 1, wherein a worm is used as the main driving gearand a worm wheel is used as the driven gear.